Difference Between Shoaling & Schooling

In nature, many species of
fish shoal or form schools, but what is the difference between shoaling fish
and schooling fish?

Any group of fish that are swimming closely together and follows
a general direction are said to be shoaling. Individual fish in a shoal may do
as it pleases. Each fish may just be scouring around for food or resting
nearby. Shoaling fish are very common in both freshwater & marine habitat.
We can even observe such behaviors in our own freshwater aquariums.

Although
shoaling fish are common in wild, but in an aquarium environment, shoaling fish
may just stop shoaling. This is usually due to the lack of predatory and
abundance of food. In such safe environment, a corydoras for example, will swim
off by itself doing its own thing since it know there are no natural predators
around. But when they are threatened, shoaling behaviors will come back again.
(please do not try frightening the fish by knocking the glass to bring back
shoaling behaviors, you will stress up the fish at the same time).

On
the other hand, schooling fish will not only swim closely together, they will
form a very tight formation and will swim in a very synchronized manner. The
schools can perform very complicated manoeuvres such as changing of directions
and turning as a whole. Schooling fish are commonly found in the marine
habitat. Some of these schooling fish are Yellowtail Fusiliers, Tuna and
Herring. The primary advantage of forming such tight schools and swimming in
coordinated manner is to minimize the chances of being eaten by larger fish.
The synchronized swimming performance also helps to confused the predators.